Hi. I'm working on a basic behind-the-scenes puzzle where you must use one circuit breaker to activate another.

I tried to set one of the buttons to start locked, but it can still be used in-game even before it is activated.

What do I do? Do I need a more advanced setup?

Hi there, you mean a button should be locked at the beginning, right? If true, you can create a logic_auto entity and you will set it up with:

OnMapSpawn
TheButtonYouWant
Lock

Be sure you set up a name to you button.